1. Field of the Invention
The present invention relates to a disk cartridge shutter opening and closing mechanism for opening and closing a shutter of a disk cartridge having a variety of disks contained in a shuttered hard case.
2. Description of the Prior Art
In general, there are conventionally known disks such as optical and magnetic disks serving as media for recording and reproducing information. Such a type of disks should be carefully handled in such a manner that their surfaces are not flawed, in order to ensure that the recorded information can be protected and also properly recorded and reproduced at all times.
Thereupon, there has been developed a disk cartridge which has a disk contained in a hard case and is designed so that a shutter can be opened when the disk is to be recorded or reproduced. This disk cartridge provides a dust-proof property and an improvement in portability for the disk, and also provides for easy handling of the disk.
FIGS. 5 and 6 show a disk cartridge 1 and a pair of arms 2A and 2B constituting a prior art disk cartridge shutter opening and closing mechanism.
The disk cartridge 1 is constituted of a thin boxlike synthetic resin hard case 3 having a disk (not shown) normally contained therein and a shutter 5 for opening and closing shutter openings 4A and 4B respectively perforated in opposite surfaces, i.e., surfaces A and B of the hard case 3. It should be noted that for convenience of understanding, the disk cartridge 1 is shown as being turned upside down from the actually used state in Figures.
More specifically, the hard case 3 is formed such that the surfaces A and B may be substantially rectangular, and the shutter openings 4A and 4B are defined substantially at the central locations of the surfaces A and B. The shutter openings 4A and 4B are provided to permit insertion of a recording and reproducing head of a disk mechanism and a disk driving mechanism (both not shown) to attain an access of them to the disk in recording or reproducing on the disk contained in the hard case 3. The shutter 5 is formed from a thin metal plate by folding into a substantially ]-shape in section, such that shutter opening blocking portions 5A and 5B covering the corresponding shutter openings 4A and 4B from the outside are connected with a fore end face 5C covering a fore end face 3C of the hard case 3 from the outside. The fore end faces 3C and 5C represent leading end faces in a direction (indicated by an arrow a in FIG. 5) of insertion of the hard case 3 into the disk mechanism. The shutter 5 is mounted to extend from a side of the fore end face 3C of the hard case 3 and over the surfaces A and B and is adapted to slide in a direction (indicated by an arrow b in FIG. 5) of width of the hard case 3 to open and close the individual shutter openings 4A and 4B by the corresponding shutter opening blocking portions 5A and 5B. The shutter 5 is also attached so that it is prevented from being released from the hard case 3 by arresting rear ends of the shutter opening blocking portions 5A and 5B from the above by means of arresting plates 6 secured on the surfaces A and B of the hard case 3 and by holding an engage piece (not shown) formed on the shutter 5 in engagement in a groove (not shown) widthwise engraved in the hard case 3. It is to be noted that for convenience, the shutter 5 is shown in FIG. 1 as being displaced to partially open the individual shutter openings 4A and 4B, but except for during recording and reproducing, the shutter 5 is biased by a return spring (not shown) to normally close the individual shutter openings 4A and 4B. In addition, during closing with the shutter 5, an engage piece (not shown) formed on the fore end face 5C of the shutter 5 is placed in engagement with a locking member (not shown) contained in the fore end 3C of the hard case 3 to lock the shutter 5.
The pair of arms 2A and 2B are provided as a mechanism for automatically opening and closing the shutter 5 when inserting and withdrawing the thus-formed disk cartridge 1 into and from the disk mechanism. One of the arms 2A serves to open and close the shutter 5, when the hard case 3 is inserted and withdrawn with the surface A above, and the other arm 2B serves to open and close the shutter 5, when the hard case 3 is inserted and withdrawn with the surface B above. Both of the arms 2A and 2B are pivotally mounted at their base ends on a housing 7 by pivots 8A and 8B, respectively, and are placed to stand by in an initial position in which shutter opening and closing pins 9A and 9B on the corresponding leading ends of the arms are automatically inserted into and engage hole 10 as an opening and closing engage means provided across a corner between the fore end face 5C and the shutter opening blocking portion 5A of the shut-off shutter 5 of the disk cartridge 1 which is being inserted.
The opening and closing of the shutter 5 of the disk cartridge 1 by the arms 2A and 2B are conducted in the following manner:
First, the disk cartridge 1 is inserted into the disk mechanism with the fore end face 3C of the hard case 3 being forward and with the surface A being down. This causes the disk cartridge 1 to be inserted into the housing 7 with the fore end face 5C of the shutter 5 being forward, until the shutter opening and closing pin 9A of the one arm 2A is inserted into the engage hole 10 defined in the shutter 5. The locking member contained in the hard case 3 is pushed inwardly into the hard case 3 to release the engagement of the engage piece of the shutter 5 with the locking member. In this case, the other arm 2B has its shutter opening and closing pin 9B abutting against the fore end face 3C of the hard case 3. Thereafter, further pushing the disk cartridge 1 into the disk mechanism causes the individual arms 2A and 2B to be pivotally moved about the corresponding pivots 8A and 8B in directions indicated by arrows c and d in FIG. 5 in such a manner that the shutter opening and closing pin 9A and 9B is pushed by the disk cartridge 1. In this case, the arms 2A and 2B are moved along the width of the hard case 3 with the shutter opening and closing pin 9A remaining engaged in the engage hole 10 in the shutter 5 and hence, the shutter moves in a direction to open the shutter openings 4A and 4B relative to the hard case 3. When the disk cartridge 1 has been pushed in to a given position, the hard case 3 is brought into abutment against a stopper (not shown) and thus stopped, while at the same time permitting the shutter 5 to fully open the shutter openings 4A and 4B. At this time, both the arms 2A and 2B are in states to intersect each other. During this opening movement of the shutter 5, the other arm 2B which is not used for opening the shutter 5 slides in such a manner that the shutter opening and closing pin 9B at its fore end rides onto the fore end face 5C of the shutter 5 from the fore end face 3C of the hard case 3.
When the shutter 5 is to be closed, the individual arms 2A and 2B, upon releasing of the safety lock (not shown), starts to pivotally move in a direction opposite to that during opening of the shutter 5 under an action of a returning resilient force biased in directions indicated by arrows e and f in FIG. 5. The pivotal movement of the arms 2A and 2B causes the disk cartridge 1 to be moved in a direction to be forced out of the housing 7, and at the same time, the shutter opening and closing pin 9A of the arm 2A is moved reversely to the opening movement, thereby causing the shutter 5 to close the individual shutter openings 4A and 4B under an action of its own returning resilient force in a closing direction. When the hard case 3 leaves the shutter opening and closing pins 9A and 9B of the arms 2A and 2B, the engage piece of the shutter 5 engages the locking member within the hard case 3 to complete the shutting-off of the individual shutter openings 4A and 4B with the shutter 5.
In each the arms 2A and 2B constituting the prior art disk cartridge shutter opening and closing mechanism, however, the following problems are encountered: Because each shutter opening and closing pin 9A, 9B used for opening and closing of the shutter 5 is mounted to rise from the arm 2A, 2B in a direction of thickness of the hard case 3, the bodies of each arms 2A and 2B must be provided at places vertically out of the thickness of the hard case 3, respectively. Therefore, a space more than the thickness of the hard case 3 is required for attaching the arms 2A and 2B, and the thickness of the housing 7 is also increased more than required, resulting in an increased size of the whole construction. In addition, when the shutter 5 is intended to be opened using the one arm 2A, the shutter opening and closing pin 9B at the fore end of the other arm 2B is permitted to initially slide, and it is then forced to invariably ride onto the fore end face 5C of the shutter 5 and subsequently slide thereon. However, a large force is required for such riding of the shutter opening and closing pin 9B onto the fore end face 5C. This causes the pushing-in force on the disk cartridge 1 to have to be increased.